We developed nanoFACS protocols for fluorescence detection and calibration, for counting, and for high-throughput sorting, to sort EV subsets from plasma and other biofluids by nanoFACS. Using multiple distinct vesicle populations, we find that nanoFACS sorting is uniquely able to produce high fidelity EV subsets (95-97% pure), with functional biological cargo (RNA and protein). Our current focus is exclusively on application of this method for clinically important studies, for the study of cancer disease burden, metastatic potential, and responses to treatment. Our NanoFACS approach that we developed as part of this ACI program is the only method currently able to analyze and preparatively sort functional EVs based on single EV characteristics, rather than bulk attributes. Furthermore, we have devised a new class of labels (Molecular NanoTags) that can be used with nanoFACS, not only to improve the detection of EV epitopes, but also to enable single molecule counting by flow cytometry. The specialized instrumentation, expertise, and biospecimen pipeline that we have assembled and are continuing to improve for this nanoFACS program does not exist anywhere else in the world, is a distinctive asset for NCI.